Most Helpful Girl
It depends how much this means to you. If you really liked her and you're feelings are hurt and don't want to, then it's perfectly ok to say no, right? she's the one who rejected you and you have a right to feel hurt. If you think you might be able to think of her as a sister or to get over your feeling for her, then I think you should say yes.
Most Helpful Guy
if you known her for a while still be her friend but if your feelings are strong then either find another or forget her.